feat(convert): add task 05 sqlite converter with variant B keys" -m "- convert: convert_sqlite.py builds tribo.db (composite PKs, enforced FKs, Q1-Q7 indexes, track_summary)

- tools: common/track_summary.py fixes the cross-engine steady-state algorithm
- rules: db-sql-schema records the FK enforcement decision and track_summary definition
- specs: 05 aligned with data-naming-units, simtra_profiles added
- docs: FK key-schema study added under docs/research/, README updated
- replace manual CSV reading with CorpusReader for better data handling
- streamline argument parsing and dependency checks using common pipeline functions
- enhance marker writing for task completion tracking
- remove unused regex and validation error classes for cleaner code

common/corpus.py

@@ -0,0 +1,73 @@
+"""Reading the CSV corpus with MANIFEST validation (converters, tasks 04-07).
+
+Every file consumed from ./out/csv/ is verified against MANIFEST.csv (byte
+size, sha256, row count) before its content is trusted - a mismatch aborts
+the converter (docs/rules/test-pipeline-validation.md section 2).
+"""
+
+from __future__ import annotations
+
+import hashlib
+import logging
+import re
+from pathlib import Path
+
+logger = logging.getLogger(__name__)
+
+MANIFEST_HEADER = "path,rows,bytes,sha256"
+
+INT_RE = re.compile(r"^-?[0-9]+$")
+FLOAT_RE = re.compile(r"^-?([0-9]+\.[0-9]*|\.[0-9]+|[0-9]+)([eE][+-]?[0-9]+)?$")
+
+
+class ValidationError(RuntimeError):
+	pass
+
+
+def coerce(s: str) -> int | float | str:
+	if INT_RE.match(s):
+		return int(s)
+	if FLOAT_RE.match(s):
+		return float(s)
+	return s
+
+
+class CorpusReader:
+	def __init__(self, csv_root: Path) -> None:
+		self.csv_root = csv_root
+		self.manifest = self._load_manifest()
+
+	def _load_manifest(self) -> dict[str, tuple[int, int, str]]:
+		manifest: dict[str, tuple[int, int, str]] = {}
+		with open(self.csv_root / "MANIFEST.csv", encoding="ascii") as fh:
+			header = fh.readline().strip()
+			if header != MANIFEST_HEADER:
+				raise ValidationError(f"MANIFEST.csv: unexpected header {header!r}")
+			for line in fh:
+				path, rows, nbytes, sha = line.strip().split(",")
+				manifest[path] = (int(rows), int(nbytes), sha)
+		logger.info("manifest loaded: %d entries", len(manifest))
+		return manifest
+
+	def read(self, relpath: str) -> tuple[list[str], list[list[str]]]:
+		"""Return (header, raw string rows), verified against MANIFEST."""
+		data = (self.csv_root / relpath).read_bytes()
+		exp_rows, exp_bytes, exp_sha = self.manifest[relpath]
+		if len(data) != exp_bytes or hashlib.sha256(data).hexdigest() != exp_sha:
+			raise ValidationError(f"{relpath}: bytes/sha256 mismatch vs MANIFEST")
+		lines = data.decode("ascii").split("\n")
+		header = lines[0].split(",")
+		rows = [ln.split(",") for ln in lines[1:] if ln]
+		if len(rows) != exp_rows:
+			raise ValidationError(f"{relpath}: {len(rows)} rows != manifest {exp_rows}")
+		return header, rows
+
+	def dicts(self, relpath: str) -> list[dict]:
+		"""Rows as dicts: lowercased CSV headers as keys, numerics coerced,
+		empty cells omitted (docs/rules/data-naming-units.md section 4)."""
+		header, rows = self.read(relpath)
+		keys = [h.lower() for h in header]
+		return [
+			{k: coerce(v) for k, v in zip(keys, row) if v != ""}
+			for row in rows
+		]